Pot type oil burner



Oct. 25, 1949. H. c. LITTLE Re. 23,158

POT TYPE OIL BURNER l Original Filed Aug. 14, 1943 2 Sheets-Sheet l 36 rlllllllllllllllll 111111,

Oct. 25, 1949. H. c. LITTLE Re- 23,158

\ POT TYPE OIL BURNER Original Filed Aug. 14, 1943 2 Sheets-Sheet 2 INVENTOR.

Reissued oct. z5, 1949 UNITED STATES PATENT OFFICE POT TYPE OIL BURNER Harry C. Little, San Rafael, Calif.

Original No. 2,401,086, dated May 28, 1946, Se-

rial No. 498,652, August 14, 1943. Application for reissue May 26, 1947, Serial No. 750,428

11 Claims. 1

The invention relates to oil burners and more particularlyto that type of oil burner wherein fuel oil is introduced into a carburator chamber and therein vaporized by heat, and mixed with air to proper combustion mixture and discharged for burning.

An object of the invention is to provide an oil burner of the character described affording improved heat output capacity for the size of the burner with clean, efficient burning conditions.

Another object of the invention is to provide an oil burner having quick starting and rapid oil vapor generating characteristics.

`Still another object of the invention is to provide an oil burner which has an improved rapid response to changes in rates of oil input in changing from high to low fire and vice versa and which becomes quickly extinguished upon cutting off of the oil intake so as to reduce to a minimum the undesirable, low, sporadic, and uncontrolled burning usually occurring in a burner of the present type when the oil flow to the burner is turned off.

The invention possesses other objects and fea tures of advantage, some of which, with the foregoing, will be set forth in the following descriptio'n of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of the specication. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawings;

Figure 1 is a vertical longitudinal sectional View taken through a burner embodying my invention.

Figure 2 is a transverse sectional view of the burner taken on the line 2-2 of Figure l.

Figure 3 is a transverse sectional view taken through the vaporizing chamber associated with the burner, the plane of the section being indicated by the line 3-3 of Figure 1.

The oil burner 6 as depicted in the accompany ing drawings consists of a container preferably of cylindrical shape defined by a bottom wall "l, a cylindrical side wall 8, and a top wall 9. Provided preferably in the bottom wall l and desirably centrally thereof, is an oil inlet opening II to which an oil delivery pipe I2 is to be connected by means of a fitting I3. Air inlet means, here in the form of a plurality of openings I4 in the side wall 8, is provided foradmitting air into the chamber for mixing with oil-vapor formed therein preparatory to burning. Formed in the top wall 9 substantially centrally thereof is a discharge opening I6, here bounded by an upstanding ange or tube I'I. The bottom wall 'I is preferably slightly dished tocause the oil to gather or puddle around the central portion of the bottom directly under the discharge opening I6.

Oil entering upon the bottom wall of the container is vaporized by reason of the heat to which the bottom of the burner is subjected, andthe generated vapor is admixed with air entering the container through the openings I4 so as to provide a burnable mixture of air and oil Vapor. As an important feature of the present invention, the burner is so designed and constructed as to set up within the container a circulation of the air and the oil vapor causing the latter to move downwardly through the central portion of the container as indicated by flow arrows I8, outwardly across the bottom of the container as indicated by now arrows I9, upwardly along the side walls of the container as indicated by flow arrows 2l, and thence inwardly across the under side of the top wall 9 as indicated by flow arrows 22. As will be noted from the drawings this circulation of air and oil vapor in toroidal convolutions, directs the hot gases downwardly towards the oil inlet opening I I and across the bottom of the pot Where the mixture is enriched by oil vapor after which the vapor and air undergo a considerable travel during which the air and vapor may become intimately mixed prior to passage out of the discharge opening I6. It is preferable in order to provide for a maximum capacity of the burner, that the circulation of the gas in the radially-directed toroidal convolutions aforesaid takes place throughout the entire` chamber, and this is obtained in part by directing streams of air radially inward at the'top of the chamber toward the throat, the velocity of such streams producing a low pressure area-at the sides which sets up a flow thereto along the bottom of the chamber and which in turn sucks a portion of the top stream downwardly from under the throat to move therewith. A preferred arrangement is illustrated in the accompanying drawings and oonsists in the using of a plurality of radial vanes 23 on the under side of the top wallQ. These vanes are preferably formed integral with and depend from the top wall and are positioned in substantially radial planes with respect to the Vertical center line of the burner and extend radially from adjacent the opening I6 to adjacent the side wall 8. As will be noted with reference to Figure 1 of the drawings, adjacent vanes 23 form with the top wall 9 a plurality of circumferentiallyspaced radially extending inverted channels which increase in circumferential width towards their outer ends. Cooperating with the provision of the vanes is the positioning and concentration of the air openings I4 at the upper end of the wall 8 so as to direct the incoming air horizontally into the pot at the under side of the top wall 9 between the vanes 23. As will be seen from Figure l of the drawings a plurality of three openings I4a, I4b, and I4c are arranged in a substantially vertical line but all are within the vertical dimension of the channel. Preferably these openings at .the outer ends of the channels are the only air inlet openings to the container so that the total air input to the container is located directly under the top wall 9 and Within the confines of the channels. It is alsov important to note that this concentration and confinement ofthe openings at the top of the side wall 8 with the resultant low pressure produced thereat materially induces the upward flow of the vapor along the wall. Because of the radial pattern of the vanes and the resulting converging of the channels towards the center of the container, incoming air is guided in independent streams towards the center of the container where a portion of the air will be impressed with a downward component of movement as a part of the circulatory movement within the container as above described- The vanes 23 also provide another very important function in absorbing heat from the air and oil vapor so as to restrain burning and facilitate -mixing of the air and oil vapor in they channels. In the circulatory effect above described, a substantial portion of the-incoming air is forced downwardly to pick up oil Vapor along the bottomof the container and the air and oil vapor is induced as above explained` to move up the side wall and back through the channels where a portion of the mixture is aga-in deflected downwardly While another portion is drawn off from the circulating gases and into they discharge opening I6 by reason of the reduced stack pressure. Thus in operation the mass of air and oil vapor continues to circulate in the manner described gradually enriching the mass with oil vapor and passing off into the discharge opening for burning. Under normal operations some burning takes place in the container thus producing heat.

for vaporizing the oill and for accelerating the circulatory movement. Due however to the cooling effect of the vanes little or no burning takes place within the channels. best results'v are obtained when three openings, rather` than a lesser or greater number of openings, are used at the outer ends of the channels. and when the center of the three openings, I4b is made substantially larger than the upper and. lower openings .Ida and Mc. The arrangement of the air openings in the manner described appears to have a substantial effect on the desirable circulating effect Within the burner. The. entering air streams have an ejector action, driving the gases inwardly through the channels and at the same time drawing the gases upwardly as4 aforesaid along the side wall and into the channels. The lower row of air openings I4c provides, primary air for premixing with the oil vapor.. The middle row of openings, Mb, provide the main'air jets as aforesaid and the air issuing therefrom supports the primary combustion within the container. The top row of openings4 Ma provide air streams which for the most part are confined to the underside of the top wall` 9.

I have found that.

and pass into the discharge opening I6 for suppor'ting the main secondary combustion above the burner. One important advantage in coniining the air inlet openings to the top of the side wall 8 is the provision of an imperforate container over substantially its full height, thus effectively avoiding the danger of an oil overflow from the container when the oil builds up from its usual depth on the bottom wall before the auxiliary automatic level control valve operates to shut oif the oil flow.

Preferably and as herein illustrated means is provided for air cooling the top wall 9 of the burner so. as to remove the heat absorbed by the vanes 23. When in the installation of the burner air is permitted to freely circulate around and across the top Wall of the burner at the outer side thereof, this eiect can be accomplished. In the present burner, however, a cooling of the top wall 9 of the burner is obtained by passing secondary air across the upper side ofl the top wall. As shown in Figure 1, the present burner is adapted for use with and is shown operatively connected to a heater casing '24 providing a combustion chamber and including, of the portion Yhere, shown, a side wall 26 and a bottom wall 21, the latter being here formed with a burner opening 28 for receiving the gases discharged from the burner. The burner may be vsecured in place under the heater casing with the discharge opening of the burner in registration with the burner opening of the casing,l by any suitable means suchV from Figure l, the burner is preferably supported with the top wall thereof spaced from the bottom wall 21 of the casing so as to denne an air space therebetween. In the preferred embodiment of the invention as hereinl depicted, the opening 28 in the heater casing is bounded by an upstanding flange 3l of somewhat greater diameter than the flange I1 on the top of the burner so as to denne therebetween an annular passage 32 which connects the passage 33 between the top wall 9 of the burner and the bottom wall 21v of the casing with the interior of the casing for supplying secondary air thereto. In order to improve the heat exchange relation within the pas-l sage 33, I prefer to. mount on the upper side of the top wall 9 of the burner a plurality of radial fins` or vanes 34 which assist in dissipating the heat from the top wall of the burner and also function to preheat the secondary air before the latter enters the combustion chamber.

As another improved feature of the present construction, flame concentration means is provided at the upper end of the burner throat. As here shown, this means consists of a plurality of overhanging portions 36. which are positioned in substantially spaced relation around the top perimeter of the flange 3| Iand extend inwardly therefrom over the top of ange I1 so as to denne a cross-shaped top opening for the burner throat. As will be best seen from Figure 3 the opposed edges 31 and 38 of adjacent overhanging portions 36 are formed in substantially parallel relation thus functioning to direct air and oil vapor issuing laterally from the under side of the portions 36 at such edges in opposite clashing streams pro-l It will be seen from the drawing that a material portion of the stream of air and fuel vapor mixture rising from the vaporizing chamber and passing through the discharge opening will, upon approaching the throat opening 2B, impinge against the underside of the overhanging portions 36 and will be deflected thereby radially inwardly of and toward the axis of the flow thus somewhat compressing the flow and causing the deflected portions to bedriven substantially toward the center thereof. It will be also noted that the secondary air enters the stream at a point below the burner throat and before the aforesaid radial deflection of the flow takes place. Thus the secondary air by entering the stream in a plurality of directions radially thereof serves, with the assistance of the overhanging portions 36 to completely intermix the fuel mixture and secondary air before the stream finally issues from the burner throat. Complete combustion of the fuel mixture is thereby assured and the fullest possible thermal output of the burner is thereby realized.

As will be seen from the drawings, the overhanging portions 3d while being of an area large enough to provide for substantial radial inward concentration of the now of the mixture through the throat, the area of all the open space left between the portions is at least substantially equal to the combined area of the portions themselves. In this way, the advantages produced by the inclusion of the overhanging members will not impede the effective free flow of the rising column at and above the area at which the secondary air enters the throat.

The burner may be used as either a natural or forced draft type. When used as a natural draft burner,V the reduced pressure in the stack (not shown) connected to the combustion casing 24, induces the circulation 'through the burner. The burner may, however, as is well known in the art, be operated under forced draft, with very substantially improved operation. by forcing the air through the openings I4 and the secondary air passage 34 by an elevated pressure. This may be accomplished by enclosing the burner or at least the air inta-ke end of the air passages in a chamber o1' manifold connected to an air blower. In either case, Whether natural or forced draft, the

burner as herein described provides many imr portant advantages over burners of this general type heretofore available. The burner starts readily on ignition of oil on the bottom thereof and rapidly generates suflicient vapor to quickly pass through the early stages of burning to full operation. Due to the toroidal circulatory action within the burner, a minimum quantity of oil is present within the burner during operation and hence the burner is more responsive to changes in oil input throughout all operating stages. Of particular advantage is the rapid extinguishment of the flame upon cutting olf of the oil flow so as `to reduce to a minimum the undesirable last minute, sporadic burning which usually occurs before the burner nnally gees out. The circulatory action of the gases within theburner produces an unusually high capacity for the size of the-burner and insures better mixing of the air and oil vapor with resultant cleaner and more eiicient burning.

I claim:

1. In an oil burner, a. container having bottom and side and top walls, means for admitting oil to said container, means for admitting air to said container, said top wall having a discharge opening centrally thereof, and a plurality of radially extending vanes mounted on the under side of said top wall and extending from adjacent said side wall to adjacent said opening for guiding the movement of air from said side wall to said opening.

2. In an oil burner, a container having bottom and side and top walls, means for admitting oil to said container for heating and vaporizing and mixture with air for burning, said top wall having a discharge opening centrally tl'iereof,- a plurality of vanes carried by said top wall and extending radially thereon with respect to saidopening from adjacent the outer periphery of said top wall to adjacent said opening, said side wall having openings for admitting air to said container through said side Wall adjacent the outer edges of said vanes.

3. In an oil burner, a container defined by a substantially cylindrical side wall anddisc-like bottom and top walls, means for admitting oil to said container for vaporizing and mixing with air for burning, said top wall having a discharge opening centrally thereof, a plurality of vanes mounted on and depending from said top wall and extending from adjacent said opening to adjacent said side wall, said vanes being formed and mounted in substantially radial planes with respect to the longitudinal axis o-f said container and `providingI a plurality of inverted channels each increasing in width towards the radially outer end thereof, said side walls being formed with air openings providing the exclusive means of air entry to the container.

4. In an oil burner, a container having bottom and top and side walls, oil inlet means provided on said bottom wall substantially centrally thereof for admitting oil onto said bottom wall for Vaporization and mixing with air for burning, said top wall having a discharge opening therein substantially centrally thereof, and a plurality of vanes mounted on and depending from said top wall and providing separate open-bottomed -passages extending substantially radially with respect to said discharge opening from adjacent said opening to adjacent said side wall, said side wall being formed'with aplurality of air inlet openings adjacent the top thereof and leading to said pas-- sages between said vanes for entry of air into Said container horizontally across the underside of said top Wall, said vanes functioning to guide said air radially inward in a plurality of independent streams.

5. In an oil burner, a container having bottom and side and top walls, means for admitting oil to Said container, means for admitting air to said container, said top Iwall having a discharge opening centrally thereof and spaced from said side Wall, a plurality of `Varies attached in heat transfer relation to said top wall and depending therefrom in said container and extending from adjacent said opening to adjacent said side wall, and means cooperating with said top walland defining an air passage at the outer side of said top wall from adjacent the outer periphery thereof to adjacent said opening, and heat radiating means attached to said top Wall and mounted in said air passage. I

6. In an oil burner, a container having a bottom and top and side walls, means for admitting oil to said container, means for admitting air to `.said container substantially exclusively adjacent said top wall, said top wall having a discharge the under side of said top wall providing separate passages for directing said air radially inwardly of said side wall toward said discharge opening.

7. An oil burner throat construction adapted for mounting, Within a heater casing, for delivering an air and vapor mixture into saidheater casing, comprising in combination with a casing` and an oil vaporizing and air mixing chamber, a

corresponding to the spacing between said annular walls, the edges of adjacent projecting portions being parallel and defining branch passages from said first air passage to said heater casing.

8. In an oil burner, a container having bottom and side Walls, an vupper wall extending inwardly from said side wall and above said bottom wall to form an oil vaporization chamber, said upper wall having a discharge opening centrally thereof, said side wall having air admission openings adjacentthe top wall and being substantially imperforate between said openings and the bottom wall, and means providing `guiding passages for directing air from said openings inwardly along said top wall towards said'discharge opening,

9. In an oil burner, a container having an oil vaporizing and air mixing chamber therein and provided with a discharge throat in an upper portion thereof, means for admitting oil to said container for ignition Vin said chamber, means for admitting primary air to said chamber for admixture with oil vapor therein to form a combustion mixture which may flow through said throat, means below the ,top of said throat for introducing secondary air to the combustion mixture flowing through said throat, and means at the top of said throat acting on said combustion mixture after the introduction of said secondary air thereto for effecting a radial concentration of said iiow toward the axis thereof as it passes through said. throat, said last means comprising circumfer` entially spaced portions directly over the throat at the periphery thereof, the combined eii'ective transverse area of said portions being less than the total transverse area of the spaces between said portions.

10. In an oil burner, a container having an oil Vaporizing and air mixing chamber therein and isv 8 provided with a discharge throat at the upper portion thereof, means for admitting eil to said container for ignition in saidcombustion chamber, meansl for admitting primary air to said combustion chamber for admixture with oil Vapor therein, said/throat being of a form to cause the mixture to flow upwardly therein in a substantially cylindrical column from said chamber, means for introducing secondary air to the column below the topl of the throat and inwardly-projecting substantially-coplanar members spaced immediately above said last means overlying the flow path of saidcolumn of combustible mixture for intercepting portions of said ow and for eiiecting a radial concentration of said flow to- Ward the axis of the Alatter as the flow passes through said throat, the combined effective trans- Verse area of said members being less than `the total transverse area of the spaces between said members. l

11. An oil burner throat construction adapted for mounting within a heater casing for delivering an air and vapor mixture into said heater casing, comprising, in combination with a casing and an oil vaporizing and air mixing chamber, a substantially vertical annular Wall having a lower end opening leading into the interior of said chamber and an upper end opening extending toward said heater casing, a second substantially vertical annular wall concentric with said iirst wall and deiining therewith an annular air passage, said second lwall extending higher than the first wall, and a plurality of circumferentially-spaced inwardly projecting substantially coplanar portions extending from said second wall in spaced relation over the upper end of said rst wall and the opening at such end, the edges of adjacent projecting portions deiining branch passages from said first air passage to said heater casing, and the space between said edges adjacent the second wall being substantially no less than the width of the projections adjacent said wall.

HARRY C. LITTLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number NameV Date 1,897,314 Little Feb. 14, 1933 2,072,048 Leonard Feb. 23, 1937 2,074,087 I-Iuetteman et al. Mar. 16, 1937 2,200,861 Peoples May 14, 1940 i 2,259,743 Fletcher Oct. 21, 1941 2,287,361 Suchland June 23, 1942 12,337,673 McCurtain Dec. 28, 1943 

